Smoking articles, (e.g., cigarettes, cigars, pipes, etc.), smokeless tobacco products (e.g., chewing tobacco, snuff, snus, etc.), and heat-not-burn products are made from natural tobacco, reconstituted tobacco, and blends thereof. Reconstituted tobacco is a type of tobacco that is generally manufactured from natural tobacco by-products generated during the threshing of the natural tobacco leaf or during the manufacture of the tobacco article. However, some natural tobaccos, such as dark air cured, air cured, burley tobaccos, etc., may contain nitrosamines formed during the curing of tobacco, e.g., tobacco-specific nitrosamines (TSNAs) and non-tobacco-specific nitrosamines. Likewise, reconstituted tobacco formed from natural tobacco by-products may also contain nitrosamines.
Unfortunately, these nitrosamines can be found in natural tobacco, reconstituted tobacco, tobacco extracts, tobacco fibers, smoke and/or aerosol. The presence of these TSNAs may raise health concerns for users repeatedly exposed to such constituents and other harmful components. As an example, the mainstream smoke produced by these tobacco products may itself contain nitrosamines, which are either transferred from tobacco or pyro-synthesized in certain cases. As another example, smokeless tobacco products may contain these nitrosamines as well. As a result, there is a need for reducing the content of TSNAs in tobacco products among which also include reconstituted tobacco products.
Many attempts have been made in the past to reduce certain components or constituents that may be contained in the mainstream smoke. Extensive research has been conducted on nitrosamines and TSNAs, particularly in tobacco products. As such, in many cases, it has been determined that such ingredients may be unwanted in the final tobacco product. For example, U.S. Pat. No. 5,810,020 to Northway, et al. describes a process for removing TSNAs from tobacco by contacting the tobacco material with a trapping sink, wherein the trapping sink comprises a select transition metal complex which is readily nitrosated to form a nitrosyl complex with little kinetic or thermodynamic hindrance.
Despite such attempted benefits to remove TSNAs from tobacco, a need currently exists for an improved method of reducing the content of nitrosamines (e.g., TSNAs) in tobacco, in particular reconstituted tobacco. In particular, a need exists for reducing the content of nitrosamines in tobacco to a greater extent than prior attempts. Additionally, a need exists for an effective and relatively inexpensive method for reducing nitrosamines in tobacco (e.g., natural tobacco, reconstituted tobacco, tobacco extracts, tobacco fibers, blends thereof, and other tobacco-containing materials) as well as tobacco products formed therefrom.